Fresh raw blood is pumped from the killing
floor to a raw blood holding tank. Approximately an hour after the
start of the kill sufficient blood has been collected to start the
coagulation and drying process.
is pumped at a constant rate from the holding tank into the coagulator
where it is mixed with saturated steam and raised to 180 –
200 Deg. F in a continuous process. It then is centrifuged and obtains
a moisture content of approximately 60%. In this state it is a coarse
wet powder and is fed directly into the blood dryer.
The blood dryer includes a rotary drum into
which the blood is introduced and where it is brought in direct
contact with a hot air stream from a direct fired air heater. The
hot air stream dries and conveys the product in a concurrent process.
The drum is equipped with longitudinal lifting flights which repeatedly
drop the product into the axial air stream. Dwell time is approximately
15 minutes. Then the product exits the drum at an outlet moisture
of approximately 8%. The outlet moisture is obtained by controlling
the drum outlet air temperature and modulating the fuel control
system as required.
Heat transfer in the drum is mainly by convection
so that the product temperature rises slightly above the wet bulb
temperature of the drying gases (approximately 160 Deg. F) resulting
in blood meal of flash dried quality.
the rotating drum the dried blood is conveyed into the primary cyclone
where approximately 99.8% of the product is separated from the air
stream and discharged through a rotary airlock. The air with the
remaining dust is drawn into our Heliclone Separator which is a
combination air mover/skimmer. The skimmed off dust with approximately
15% of the air flow is directed into the secondary cyclone where
the collected dust is discharged through a rotary airlock. The air
flow is returned to the primary cyclone and is thus recycled.